The CuO and SnO2 co-modified Na0.52K0.48NbO3 ceramics were prepared by a conventional mixed oxide method. Densification can be further improved but the grain growth is inhibited as a small amount of SnO2 is added into 1% CuO doped Na0.52K0.48NbO3. The results indicate that the physical and various electrical properties of CuO and SnO2 doped Na0.52K0.48NbO3 ceramics significantly depend on sintering conditions and the contentofdopants. The ceramics doped with 1 mol% CuO and 1 mol%SnO2 sintered at 1070 degrees C for 3 h show improved dielectric and piezoelectric properties: d(33) = 120 pC/N, k(p) = 0.38, Q(m) = 1040, epsilon(r) = 710 and tan delta = 0.013 (1 kHz), in comparison with un-doped or CuO doped compositions. (C) 2009 Elsevier Ltd. All rights reserved.